Problem summary
Adding a mathematical expression to the X or Y values of a curve sets the values incorrectly in the Curve Editor.
Customer reported version
nuke.11.1v1
Customer reported platform
n_a_linux
Steps to reproduce
1) Open any version of Nuke and create a Checkerboard node (or any other node with values that can be keyed).
2) Move the playhead to Frame 2, and set a key on the Checkerboard's Size knob in the Properties tab. Then move the playhead to Frame 10, and change the Size value to 80 to set a second key. (Or any other knob, value, or frame).
3) Open the Curve Editor and highlight the animated knob, then double-click the second key on the curve.
4) Modify the Y value with a mathematical expression. E.g., if "64" is the current value, change the value to "64+1".
5) Modify the X value with a mathematical expression. E.g., if "80" is the current value, change the value to "80+1".
6) Observe that the Y value is set to 0, and the X value inherits the value of the previous keyframe.
Workaround
Adding the expression directly in the node's Properties will correctly set the value. This can be done in the knob's field, or via the Animation Menu > Edit expressions... menu.
Reproduced by support
Nuke 11.1v1 - Windows 10
Nuke 11.0v4 - Windows 7
Nuke 11.0v1 - Mac OS X 10.11.6 - Windows 7
Nuke 10.5v7 - Windows 7
Nuke 10.5v1 - Windows 7
Nuke 10.0v6 - Windows 7
Nuke 10.0v1 - Windows 7
Nuke 9.0v9 - CentOS 7.4
Nuke 9.0v1 - Windows 7
Nuke 8.0v7 - Windows 7
Nuke 8.0v1 - Windows 7
Nuke 7.0v10 - Windows 7
Earliest version tested
Nuke 7.0v10 - This issue appears to occur in all versions of Nuke.
Expected behavior
The value of the modified keyframe should move to the correct position.
Actual behavior
When a mathematical expression is added to the Y value of the keyframe, the Y value is reset to 0.
When a mathematical expression is added to the X value of the keyframe, the X value inherits the value of the previous keyframe.